Rotary electromagnetic transfer switch



May 15, 1951 H. E. SCHLEICHER 2,553,478

ROTARY ELECTROMAGNETIC TRANSFER SWITCH Filed Oct. 26, 1944 4Sheets-Sheet 1 IN V EN TOR. f/zzm/d A". 50/1 iez'c/rer May 15, 1951 H.E. SCHLEICHER ROTARY ELECTROMAGNETIC TRANSFER SWITCH 4 Sheets-Sheet 2Filed Oct. 26, 1944 I INVENTOR. Hera/d 1?. 50 4 [Eff/I6! BY I May 15,1951 H. E. SCHLEICHER ROTARY ELECTROMAGNETIC TRANSFER SWITCH 4Sheets-Sheet 3 Filed Oct. 26, 1944 IN VEN TOR. Zia/01d E. 50/? leis/2e)May 15, 1951 H. E. SCHLEICHER 2,553,473

' ROTARY ELECTROMAGNETIC TRANSFER SWITCH F iled Oct. 26, 1944 4Sheets-Sheet 4 FIG 7 NORMAL SUPPLY LOAD (DEENERGIZED CONDITION)EMERGENCY SUPPLY IN VEN TOR. r0 02 E. Sable/MW E MMWM 1 12210}? NEY-S'Patented May 15, 1951 ROTARY ELECTROMAGNETIC TRANSFER SWITCH Harold E.Schleicher, West Hartford, Conn., as-

signor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., acorporation of Connecticut Application October 26, 1944, Serial No.560,407

Claims.

v 1 This invention relates to rotary magnetic switches of balancedshockproof type and represents an improvement upon and a new applicationof the similar invention described andclaimed in my co-pendingapplication, Serial No. 511,855 entitled Rotary Magnetic Switch andfiled November 26, 1943, now Patent No. 2,540,294, February 6, 1951.

It is an object of the invention to provide in a switch of the abovetype a fully enclosed electromagnetic operating mechanism which may bemounted directly on a panel with switching sections built on in anydesired number to suit requirements.

Another object is to provide manual operating means available from thefront of the panel when the switch is on the back with optionally usablemeans to lock the manual operating means and switch in any of three(emergency, normal or neutral) positions.

Another object is to provide a switch structure of the foregoing typeutilizing a minimum number of insulating bodies or discs per polearranged in a compact manner and using a minimum number of conductiveparts.

Another object is to provide means for interchangeably positioning amovable switch memher in any of a number of different positions on themain shaft, whereby said movable member may normally occupy either anopen or a closed position as desired.

Another object is to provide an electromagnetic switch constructed foruse as a transfer switch and embodying a coil circuiting arrangementwhich will cause armature actuation i. e. pickup, or release i. e.drop-out at voltage conditions and values that are closely related.

Other objects and advantages of the invention will become apparent as itis described in connection with the accompanying drawings.

Although the device will be described in connection with a preferredform and use as a transfer switch, it should be understood that it isnot limited in that respect.

In some conventional circuits there are two sources of power supply. Oneis a normal source, such as a generator which is used when allconditions are normal. The other is an emergency source such as storagebatteries which is used when something goes wrong affecting the normalsupply. At such time it is desirable to shift over automatically to theemergency supply.

In the. drawings, wherein like numerals refer to like parts, Figure 1 isa side elevation view, partly in section, of a switch embodying theinvention; Figure 2 is an end elevation view of the switch illustratedin Fig. 1; Figure 3 is a transverse section view taken along line 33 ofFig. 1; Figures 4 and 5 are section views taken along lines 4--4 and 5-5respectively of Fig. 1; Figure 6 is a view looking into the face of discB when disc C and the remaining discs at the right end of Fig. l havebeen removed. In Figures 3, 4, 5 and 6 the parts are in neutralposition. Figure 7 is a circuit diagram of one use of the invention.

Referring to the drawings and particularly to Fig. 1 thereof, the switchis adapted to be mounted in back of a panel P with a handle 20 in frontof the panel mounted upon an extension 22c of the main shaft 22 of theswitch.

The operating mechanism for electromagnetically controlling the movementof the switch is of the type disclosed in my co-pending application S.N. 511,855 supra and may be generally described as comprising a pair oftoroidal solenoid coils 24, 26 mounted upon core members 28, 30. Theelectromagnetic operating structure is also described and is claimed inmy application Serial No. 185,422 filed September 18, 1950, entitledElectromagnetic Operating Means For Rotary Electric Switches and otherDevices, which is a division of said application Serial No. 511,855.

A Z-shaped armature 32 has arms of arcuate shape adapted to move intothe toroidal solenoid coils as the coils become energized. The armatureis mounted upon the main shaft 22 of the switch which is preferably ofsquare section and passes through a square central aperture in thearmature so that the armature and shaft turn together.

The parts of the electromagnetic mechanism are housed within acup-shaped housing 34 whose open front is adapted to lie flush againstthe panel P. For securing the housing 34 to the panel a rectangularflange is formed on the open front peripheral edge 34 of the housing.The four corners of this flange are apertured for the reception ofsecuring bolts which may pass through the panel P. The electromagneticmechanism may be enclosed within the housing by a circular cover plate36. Preferably the housing and the cover plate will be made of magneticmaterial to confine stray electro-magnetic flux.

For biasing the electro-magnet armature into deenergized position a coilspring 38 is provided within the housing 34 and wound around the mainshaft of the device. One end of said spring presses against a fixed lug40 and the other end 3 of the spring presses against a lug 42 movingwith the magnet armature.

The insulating base or body of the switch is built up from a number ofidentical circular molded insulating discs, such as A, B, C and D.Referring to Figures 1 and 5, each face of each disc is annularlyrecessed, as at A| (for convenience the numerals such as l, 2, 3 areused to designate the various parts of the disc structure and theletters A, B and C are used in connection with these numerals todesignate the particular disc referred to). The adjoining recesses inopposite faces of the adjoining discs, such as A-'l, B-I provide achamber within which the several movable contact members, presently tobe described, are adapted to rotate. Within each recess are concentriclow annular ridges or'ribssuch as A2, A3. Each disc has a circularopening at its center for the main shaft 22. At diametrically oppositepositions in one face of each disc are pairs of spaced radial grooves,for example A4 and A5, A5 and Al, each pair of grooves being connectedby an arcuate channel such as A8 and A9.

When the switch is used as a transfer switch the disc A will have placedin its grooves A5 and A6, stationary contact and terminal members 59, 52stamped from sheet metal each with a flat central portion fitting in thegroove, and laterally enlarged-inner ends 500 and 520 forming contactsextending into the annular recess or cavity formedby the recesses Al andBi.

Flat insulating plugs 54 may fill the unused grooves A4 and A1.

For bridging the contacts 550 and 520 there may be mounted'on the mainshaft a symmetrical balanced rotarycontact member designated generallyby 55 and comprised of a pair of flexible conductive blades 56 of theshape illustrated, lying against opposite sides of an insulating spacingdisc 5? and having laid against their opposite sides larger insulatingguide discs "58. Rivets passing transversely through all the elements ofthe movable contact member may secure them together. In the center ofthe assembled member is an eight-point star-shaped aperture 59 by meansof which it is possible to place the contact member in any of eightpositions on the square main shaft 22.

As the adjacent sections are fitted together the ribs A3 and B3 of thedisc facing each other afford guides for the rotary movement of thecontact within the chamber formed by the joining recesses Al, Bl.

The movable contact 55 between discs A and B may be placed on the shaft22 so as to engage the fixed contacts 52, 55 when the coils aredeenergized. In that case if the coils are connected as illustrateddigrammatically in Fig. '7 (wherein like reference numerals refer tolike parts of other figures) only one (24) of the solenoid coils willoperate as a closing coil for moving the shaft upon energization. Theother coil is shunted and only becomes encircuited when the contact 55opens the shunt circuit. But the coil 26 may jointly exercise a holdingfunction with the coil 24 to maintain the switch in energized positionmore effectively than the energizing force exercised by one coil alone.

Discs B and C are illustrative and typical of one pole of the multi-poleswitch illustrated in Figure 1. On the disc B (Fig. 6) a stationarycontact Bl] comprising a central conductive bar portion, an inwardlyextending contact supporting portion and an exteriorly extendingterminal portion is laid in the groove B4.

A block of good contact material 680 is soldered or welded to one edgeof the end of the contact member which extends into the cavity formed byadjoining recesses B! and CI in the opposite faces of the discs B and C.This contact member 6!] is secured in position by a bolt 62 passingthrough the disc B, the bolt head being counter-sunk.

Another stationary contact is adapted to fit in the groove B1 and isidentical to the contact 55 but though lying in groove B? it is securedagainst the face of the surface of the adjoining section disc C by abolt 65 extending through disc C into a screw-threaded aperture in saidcontact B4. The bolt also serves to electrically connect contact 64 to acontact and terminal member designated generally by numeral 68 on theother side of disc C.

The contact and terminal member 68 is a sheet metal stamping having afiat portion 68d lying in thegroove C6 and from which extends inwardly acontact portion 6'80. Laterally extending from portion 5811 is anarcuate bar portion 58a seating in the arcuate channel C8 to connectwith a terminal plate portion 68b fitting into the groove C1. The screw68 connects this terminal portion with the contact '54 on opposite sidesof disc C. Diametrically opposite the contact portion of contact 68, andin groove C5 is a contact and terminal it identical to contact-terminal68 (but facing in counterclockwise instead of clockwise direction).

The movable contact members which are adapted to connect the stationarycontacts 5?. and .64 between discs B and C, and the stationary contacts58 and "Ill between discs C and D are identical and are similarinstructure to the movable contact members disclosed in my co-pendingapplication SJN. 5'11, 855 supra.

These movable contact members are insulated from the main shaft 22, onwhich they are mounted,'by an insulating sleeve 53 slipped onto theshaft.

Since the details of the movable contact form no part of the presentinvention and are disclosed in said prior copending application, it needonly be mentioned that the bridging contacts .are-formedas illustratedand are dynamically balanced. Thebridging elements of these contacts areformed from heavy sheet metal with radial arms such as 721) on the endedges of which are aifixed contact blocks, such as 2'20,

for engagement with the fixed contact block (Elle for example). Thebridging elements are moved bythe shaft 22, there being a resilient lostmotion connection therebetween as in my prior application whichtherefore'need not be described in detail.

To enable mounting the movable contact member on the shaft in differentangular positions an eight point star-shaped aperture is provided at12a.

It will be apparent'to those skilled in the art that the normalcondition may be with the solenoid coilsenergized. In such a case thefailure of .the normal supply will cause deenergization of the holdingcoils, both of which will then become deenergized permitting the switchto open under the effort of the biasing spring 38.

When used as a transfer switch the movable contact member 12 betweendiscs B and C may be positionedon shaft 22 so as to be normallydisengaged Lfrom-contacts .60 and 64; and the movable contact element"82 between discs C and D may benormally engaged with its complementarystationary contacts68 andlll. Thus when an emergency condition occursthe electromagnetic operating mechanism will release the shaft 22 whichwill be turned by spring 38 to disengage the movable contact 82 fromcontacts 68 and I9 and will engage the contact I2 with contacts 69 and64, thus transferring the load connected with terminal 651E from thenormal line supply connected to contact Hi to the emergency supplyconnected with the terminal 60. Concomitantly the switch member 55 whichhas been disconnected from contacts 50 and 52 will engage those contactsto which the leads of one of the solenoid coils, for example 26, areconnected. Thus that coil will now be bridged by the contact 55 and willbecome shunted out of action.

On resumption of normal service supply the coil 24 will become energizedalone causing the electro-magnet to operate the switch. That will openthe contact 55 which will permit the solenoid coil 26 to becomeenergized in series with the coil 2 so that both will jointly hold theswitch for normal supply.

In order that the switch may be locked in either normal or in emergencyposition, or if occasion demands in the neutral off position, thereareprovided in underside of the handle 20 three spaced recesses 20c, 2021m for the reception of a locking pin 90. This pin is mounted in a bossor collar 92 affixed to the cover 36 of the electromagnet operatingmechanism. Said boss or collar is internally'bored and screw-threaded tore ceive an inner screw-threaded end of the locking pin. A knurledflange 94 is provided on the neck of the locking pin whereby the pin maybe screwed toward or away from the handle 20 so as to engage within orbe retracted from one or another of the holes 2012, 206 or 20 Thus,although the spring biases the shaft 22 and the handle 20 into emergencyposition, the handle may be grasped to move the shaft into normal orinto emergency positions in case manual operation is desired. In eitherof these positions or in a neutral off or switch-open position, betweennormal and emergency positions, the switch may be locked by manipulatingthe knurled flange 94 as described.

It will be understood that although I have given a detailed descriptionof only one pole of a transfer switch, the switch may be formed with anynumber of poles. In Figure 1 is illustrated three-pole transfer switch,the second and third poles being identical in structure to the one poledescribed.

The switch is not limited to use as a transfer switch. It may be usedmore generally. In any case, the bridging contact 55 in the circuit withthe solenoid coils may be placed on shaft 22 so that it will bedisengaged from the fixed contacts 56, 52 when the solenoid coils aredeenergized. The star shaped aperture 59 permits such variation inmounting. Under such conditions the contacts 50, 52, 53 may be connectedconventionally as sealing-in or holding contacts as usual inelectromagnetic switches, the term sealing-in being understood by thoseskilled in the art to refer to contacts which move closed with the maincontacts under the influence of the solenoid and close a circuit throughthe solenoid to thereby hold themselves and the main contacts closed.

From the foregoing it will be observed that the invention provides abalanced rotary magnetic transfer switch having a double throw contactarrangement on a single shaft controlled by a single armature.

No mechanical interlock is necessary since there is energization in oneposition or direction only. The invention also provides for manualemergency control in case it should become necessary to throw the switchin one direction or another by hand. Without detracting from-otheradvantages, the invention also provides latch means for holding theswitch in any of the three positions. The provision for holding theswitch in an intermediate or neutral position is particularly usefulwhen it becomes necessary to quickly remove contacts for servicing or todisconnect the lines from the load.

The invention provides means to meet exacting requirements, such as inNaval specifications. Conventional electromagnetic switches having asingle magnet coil (or equivalent multiple coils acting in the samemanner), if properly designed for continuous duty without overheating,Will be actuated or pick up at approximately 85% of full voltage butwill not release or drop out until the voltage has dropped toapproximately 10% of full voltage. Thus, in the usual commercial formsof electromagnets there is a wide gap between pick up and drop outvoltages. This gap is reduced materially by the present inventionthrough the utilization of dual coils in the manner described. Theinvention enables drop out at 70% to and pick up at to .of full voltage.At the same time the sealing of the magnet in actuated position is moreefliciently accomplished.

Many modifications within the scope of my invention will occur to thoseskilled in the art and therefore I do not limit my invention to thespecific embodiment herein shown and described.

I claim:

1. In a rotary electro-magnetic switch a main shaft means for manuallyoperating said shaft, a pair of rotary bridging contact meansconstructed and arranged for balanced movement with said shaft,electro-magnetic means for moving said bridging contact means in onedirection and comprising a rotary balanced armature mounted on saidshaft and solenoid coils acting thereon, spring means moving saidbridging contact means in the opposite direction when .said magnet isdeenergized, electrically common stationary contact means engageable byboth of said pair. of bridging contact means in different positions, andseparate stationary contact means one of which is engageable by one ofsaid pair when that one of the pair engages said common contact means,and by the other of said separate contact means being engageable by theother of said pair when said oth r of the pair engages said commoncontact means, and means to lock said pair of bridging contact means inenergized, deenergized or open-circuit positions of said shaft.

2.In a rotary electro-magnetio switch a main shaft means for manuallyoperating said shaft, a pair of rotary bridging contact meansconstructed and arranged for balanced movement with said shaft,electro-magnetic means for moving said bridging contact means in onedirection and comprising a rotary balanced armature mounted on saidshaft and solenoid coils acting thereon, spring means moving said bridging contact means in the opposite direction when said magnet isdeenergized, electrically common stationary contact means engageable byboth of said pair of bridging cont act means in different positions, andseparate stationary contact means one of which is engageable by one ofsaid pair when that one of the pair engages said common,

contact means and by the other of said separate contact means beingengageable by the other of said pair when said other of the pair engagessaid common contact means, and means to lock said pair of bridgingcontact means in energized, deenergized or open-circuit positions ofsaid shaft, comprising a handle on said shaft having recessescorresponding to said three positions, and a manually movable pinengageable within and removable from said recesses selectively at will.

3. In a rotary electro-magnetic switch, a main shaft, a pair of rotarycontact means, an electro-magnet for moving said means in one direction,spring means moving said contact means in the opposite direction whensaid magnet is deenergized, electrically common stationary contact meansengageable by both of said pair of contacts in difierent positions, andseparate stationary contact means one of which is enga eable by one ofsaid pair when that one of the pair engages said common contact means,the other of said separate contact means being engageable by the otherof said pair when said other of the pair engages said common contactmeans, a plurality of identical discs forming an insulating base forsaid switch, one of said stationary contacts and said electricallycommon contacts being secured to one disc, said other stationary contactbeing secured to an adjoining disc,- said discs having recesses toprovide an enclosed cavity between adjoining discs on movement of saidrotary contact 4. In a rotary magnetic switch, a main shaft, a pair ofrotary contact means, an electro-magnet for moving said means in onedirection, spring means moving said contact means in the oppositedirection when said magnet is deenergized, electrically commonstationary contact means engageable by both of said pair of contacts indifferent positions, and separate stationary contact means one of whichis engageable by one of said pair when that one of the pair engages saidcommon contact means, the other of said separate contact means beingengageable by the other of said pair when said other of the pair engagessaid common contact means, a plurality of identical discs forming aninsulating base and supporting said stationary contacts, said discsbeing recessed to provide an enclosed cavity between adjoining discs formovement of said rotary contact means, means to mount the switch on apanel comprising a cup-shaped casing of magnetic material for saidelectro-magnet provided with a flange adapted to lie flush against andbe secured to a panel with said main shaft perpendicular to the panel.

5. In a rotary magnetic switch, a main shaft, a pair of rotary contactmeans, an electro-magnet for moving said means in one direction, springmeans moving said contact means in the opposite direction when saidmagnet is deenergized, electrically common stationary contact meansengageable by both of said pair of contacts in diflerent positions, andseparate stationary contact means one of which is engageable by one ofsaid pair when that one of the pair engages said common contact means,the other of said separate contact means being engageable by the otherof said pair when said other of the pair engages said common contactmeans, a plurality of identical discs forming an insulating base andsupporting said stationary contacts, said discs being recessed toprovide an enclosed cavity between adjoining discs-for movement of saidrotary contact means,

means to mount the switch on a panel comprising a cup-shaped casing ofmagnetic material for said electro-magnet provided with a flange adaptedto lie flush against and be secured to a panel with said main shaftperpendicular to the panel, and means to manually operate said shaftfrom the oppos' e side of the panel.

6. In a rotary electro-magnetic switch, a main shaft, a plurality ofrotary contact means constructed and arranged in balanced relationthereon, an electro-magnet for holding said con tact means in oneposition, spring means moving said contact means into another positionwhen said electro-magnet is deenergized, said electromagnet comprisingan armature constructed and arranged on said shaft in balanced relation,toroida'l solenoid coils acting on said armature, fixed contactsengageable by one of the rotary contact means and connected to oppositeends of one of said toroidal coils, other fixed contacts engageable byanother of said rotary contact means when said one rotary contact meansis in openci-rcuit position, means to energize another of said coils tocause movement of said one rotary contact means from closed toopen-circuit condition and to thereupon energize the first-mentionedcoil whereby both coils act to hold said switch in energized position.

7. In a rotary electro-magnetic switch, a main shaft, a plurality ofrotary contact means constructed and arranged in balanced relationthereon, an electro-magnet for holding said contact means in oneposition, spring means moving said contact means into another positionwhen sa'id electro-magnet d'eenergized, said electromagnet comprising anarmature constructed and arranged on shaft in balanced relation, toroidal solenoid coils acting on said armature, fixed contacts engageableby one of the rotary contact means and connected to opposite ends of oneof said toroidal coils, other fixed contacts engaged by a second and athird of said rotary contact means, certain of said last-mom tionedfixed contacts being electrically common and the remainder of saidlast-mentioned contacts being adapted for connection to differentsources or power means to energize another of said coils to ea, cmovement of said first-mention'ed rotary contact means from closed toopencircuit condition and to thereupon energize the first-mentioned coilwhereby both coils hold said switch in energized position.

8. In a rotary electro-magnetic switch, a main shaft, a' plurality ofrotary contact means constructed and arranged in balanced relationthereon, an electro-ma net for holding said contact means in oneposition, spring means moving said contact means into another positionwhen said electro-magnet is deenergized, said electromagnetcomprising anarmature constructed and arranged on said shaft in balanced relation,toroidal solenoid coils acting on said armature, a plurality ofidentical insulating discs, fixed contacts mounted on one of said discsand engageable by one of the ro'tarycon-tact means and connected toopposite ends of one of said toroidal coils, other fixed contactsmounted on another of said discs and engageable by another of saidrotary contact means when said one rotary contact means is inopen-circuit position, means to energize another of said coils to causemovement of said one rotary contact means from closed to open-circuitcondition and to thereupon energize the first-mentioned coil wherebyboth coils act to hold said switch in energized position, said discsbeing recessed to form enclosed cavities between adjoining discs forsaid rotary contact means.

9. In a rotary electro-magnetic switch, an electro-magnet comprising arotary balanced armature, a main shaft rotated by said armature, fieldcoils for energizing said armature, a housing for said electro-magnetand a cover therefor both of magnetically conductive material, aplurality of identical insulating discs centrally recessed to provide acavity for fixed and moving contact members when two of said discs arenested together, said discs having in one face radial grooves, fixedline and load contact members received in said grooves and havingcontact portions extending into said cavity, rotary contact membersmounted on said main shaft and movable therewith to engage and disengagesaid fixed contacts, a securing bolt electrically and structurallyjoining two load contacts of adjacent discs, the opposed contacts insaid discs being adapted for connection to normal and emergency powerlines respectively, spring means biasing said main shaft to engage onerotary contact into engagement with the emergency and load contacts,energization of said electro-magnet causing said spring means to beovercome and to move said one rotary contact to open-circuit positionand simultaneously moving another rotary contact into engagement withthe normal and load contacts, and an insulating cover disc nestedagainst the end of said contact supporting discs.

10. In a rotary electromagnetic switch, a plurality of rotary contactmeans at least one of which is a bridging contact, an electromagnet forholding said contact means in one position against a normal bias intoanother position, said electromagnet comprising a rotary armature,solenoid coils acting on said armature, fixed contacts engageable bysaid bridging contact means and connected to opposite ends of one ofsaid coils, other fixed contacts engageable by another of said rotarycontact means when said bridging contact means is in open-circuitposition, means to energize another of said coils to cause movement ofsaid bridging contact means from closed to open-circuit condition andthereupon to energize the first mentioned coil whereby both coils act tohold said switch in energized position.

HAROLD E. SCI-ILEICHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 539,376 Bliss May 14, 1895591,491 Parkin Oct. 12, 1897 1,051,542 Bissell Jan. 28, 1915 1,207,016Fryer Dec. 5, 1916 1,426,993 Kardaetz Aug. 22, 1922 1,438,727Schwagermann Dec. 12, 1922 1,701,352 Bailey Feb. 5, 1929 1,702,035Berthold Feb. 12, 1929 1,744,930 Spencer Jan. 28, 1930 1,891,247 ShapiroDec. 20, 1932 1,913,826 Blosser June 13, 1933 2,012,492 Arnold et a1.Aug. 27, 1935 2,254,509 Bassett, Jr. Sept. 2, 1941 2,267,116 Mageoch etal. Dec. 23, 1941 2,314,291 Taylor Mar. 16, 1943 2,339,675 Bucklen eta1. Jan. 18, 1944 2,393,535 Horman Jan. 22, 1946

